1. Technical Field
The present invention relates to a power semiconductor module.
2. Description of the Related Art
In the power semiconductor module, a high-capacity power semiconductor module uses a plurality of power devices which are connected to each other in parallel, due to a limitation of the power device. That is, according to the power semiconductor module published in (Patent Document 1), the high-capacity power semiconductor module is configured by mounting the plurality of power devices on a base plate and connecting the power devices in parallel to easily accommodate a high-capacity current.
The high-capacity power semiconductor module according to the related art, including the (Patent Document 1) has a problem in that there is a need to uniformly control each power device and the power devices are disposed only in a limited space and a limited number of power devices are connected to each other in parallel due to an unbalance of a heat generation problem between the power devices, and the like.
Therefore, to resolve the heat generation problem of the power device, in addition to a generally used heat radiating substrate, various efforts have been conducted, but do not obtain distinct outcomes.
Meanwhile, in the high-capacity power semiconductor module, terminals which are external terminals are connected to each other by generally using soldering, ultrasonic bonding, or wire bonding, which is disclosed in (Patent Document 1) and (Patent Document 2).
Here, a structure of connecting between the terminals by the soldering has a problem of reliability of bonded portions between the terminals, and uses a reflow process at the time of connecting between the terminals to increase package cost and reduce productivity and a reliability such as remelting of other bonded portions during the reflow process.
Further, similar to the soldering, the structure of connecting between the terminals by the ultrasonic bonding also causes the reliability problem and requires separate equipment for the ultrasonic bonding process and therefore causes an increase in cost in the package process. Further, even when the terminals are connected to each other by the wire bonding, a large current accommodating capacity of the wire bonding is limited and therefore the rating of the power semiconductor module is limited or a lot of wire bonding needs to be performed to make a large current flow, thereby causing the reliability problem, the increase in the package cost, and the like.